From: Leilei Shang <[email protected]> To enter high speed mode, following steps should be done: 1. When running in high speed mode, i2c clock rate is different from standard mode. Clock rate must be set according to specification first. 2. When I2C controller sends a master code and wins arbitration, high speed mode is entered.
If you want to enable high speed mode, the following members of platform data should be set to proper value: 1. "high_mode" should be set to "1". 2. "master_code" should be set to "8'b 0000_1xxx"(x is 0 or 1). If no master_code is set, set to default value 0xe. 3. "rate" should be set according to specification. Signed-off-by: Leilei Shang <[email protected]> --- drivers/i2c/busses/i2c-pxa.c | 68 +++++++++++++++++++++++++++++++++++++++++- include/linux/i2c/pxa-i2c.h | 3 ++ 2 files changed, 70 insertions(+), 1 deletions(-) diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c index 3a5c477..da7b9ae 100644 --- a/drivers/i2c/busses/i2c-pxa.c +++ b/drivers/i2c/busses/i2c-pxa.c @@ -119,6 +119,8 @@ MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table); #define ICR_SADIE (1 << 13) /* slave address detected int enable */ #define ICR_UR (1 << 14) /* unit reset */ #define ICR_FM (1 << 15) /* fast mode */ +#define ICR_HS (1 << 16) /* High Speed mode */ +#define ICR_GPIOEN (1 << 19) /* enable GPIO mode for SCL in HS */ #define ISR_RWM (1 << 0) /* read/write mode */ #define ISR_ACKNAK (1 << 1) /* ack/nak status */ @@ -164,6 +166,10 @@ struct pxa_i2c { int irq; unsigned int use_pio :1; unsigned int fast_mode :1; + unsigned int high_mode:1; + unsigned char master_code; + unsigned long rate; + bool highmode_enter; }; #define _IBMR(i2c) ((i2c)->reg_ibmr) @@ -468,6 +474,7 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c) /* set control register values */ writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c)); + writel(readl(_ICR(i2c)) | (i2c->high_mode ? ICR_HS : 0), _ICR(i2c)); #ifdef CONFIG_I2C_PXA_SLAVE dev_info(&i2c->adap.dev, "Enabling slave mode\n"); @@ -689,6 +696,34 @@ static int i2c_pxa_pio_set_master(struct pxa_i2c *i2c) return 0; } +/* + * PXA I2C send master code + * 1. Load master code to IDBR and send it. + * Note for HS mode, set ICR [GPIOEN]. + * 2. Wait until win arbitration. + */ +static int i2c_pxa_send_mastercode(struct pxa_i2c *i2c) +{ + u32 icr; + long timeout; + + spin_lock_irq(&i2c->lock); + i2c->highmode_enter = true; + writel(i2c->master_code, _IDBR(i2c)); + + icr = readl(_ICR(i2c)) & ~(ICR_STOP | ICR_ALDIE); + icr |= ICR_GPIOEN | ICR_START | ICR_TB | ICR_ITEIE; + writel(icr, _ICR(i2c)); + + spin_unlock_irq(&i2c->lock); + timeout = wait_event_timeout(i2c->wait, + i2c->highmode_enter == false, HZ * 1); + + i2c->highmode_enter = false; + + return (timeout == 0) ? I2C_RETRY : 0; +} + static int i2c_pxa_do_pio_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) { @@ -752,6 +787,14 @@ static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) goto out; } + if (i2c->high_mode) { + ret = i2c_pxa_send_mastercode(i2c); + if (ret) { + dev_err(&i2c->adap.dev, "i2c_pxa_send_mastercode timeout\n"); + goto out; + } + } + spin_lock_irq(&i2c->lock); i2c->msg = msg; @@ -999,11 +1042,14 @@ static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id) i2c_pxa_slave_txempty(i2c, isr); if (isr & ISR_IRF) i2c_pxa_slave_rxfull(i2c, isr); - } else if (i2c->msg) { + } else if (i2c->msg && (!i2c->highmode_enter)) { if (isr & ISR_ITE) i2c_pxa_irq_txempty(i2c, isr); if (isr & ISR_IRF) i2c_pxa_irq_rxfull(i2c, isr); + } else if ((isr & ISR_ITE) && i2c->highmode_enter) { + i2c->highmode_enter = false; + wake_up(&i2c->wait); } else { i2c_pxa_scream_blue_murder(i2c, "spurious irq"); } @@ -1088,6 +1134,11 @@ static int i2c_pxa_probe_pdata(struct platform_device *pdev, if (plat) { i2c->use_pio = plat->use_pio; i2c->fast_mode = plat->fast_mode; + i2c->high_mode = plat->high_mode; + i2c->master_code = plat->master_code; + if (!i2c->master_code) + i2c->master_code = 0xe; + i2c->rate = plat->rate; } return 0; } @@ -1160,6 +1211,7 @@ static int i2c_pxa_probe(struct platform_device *dev) i2c->irq = irq; i2c->slave_addr = I2C_PXA_SLAVE_ADDR; + i2c->highmode_enter = false; if (plat) { #ifdef CONFIG_I2C_PXA_SLAVE @@ -1169,6 +1221,20 @@ static int i2c_pxa_probe(struct platform_device *dev) i2c->adap.class = plat->class; } + if (i2c->high_mode) { + if (i2c_type != REGS_PXA910) { + pr_warn("i2c: <%s> do not support HS mode\n", + i2c->adap.name); + i2c->high_mode = 0; + } else if (i2c->rate) { + clk_set_rate(i2c->clk, i2c->rate); + pr_info("i2c: <%s> set rate to %ld\n", + i2c->adap.name, clk_get_rate(i2c->clk)); + } else + pr_warn("i2c: <%s> clock rate not set\n", + i2c->adap.name); + } + clk_prepare_enable(i2c->clk); if (i2c->use_pio) { diff --git a/include/linux/i2c/pxa-i2c.h b/include/linux/i2c/pxa-i2c.h index 1a9f65e..53aab24 100644 --- a/include/linux/i2c/pxa-i2c.h +++ b/include/linux/i2c/pxa-i2c.h @@ -67,6 +67,9 @@ struct i2c_pxa_platform_data { unsigned int class; unsigned int use_pio :1; unsigned int fast_mode :1; + unsigned int high_mode:1; + unsigned char master_code; + unsigned long rate; }; extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info); -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
